Investigation Of EphA2on The Paclitaxel Resistance In Nasopharyngeal Carcinoma Via Regulating P-gp And Autophagy In Vitro

Objective:To investigate the potential molecular mechanisms of EphA2in nasopharyngeal carcinoma (NPC) paclitaxel resistance.Methods:Firstly, Western Blot was applied to detect the expression of P-gp protein in EphA2up-regulated and down-regulated groups as well as the corresponding control groups; Secondly, P-gp protein was down-regulated by siRNA interfering, and CCK-8assay was employed to obtain the survival rate of paclitaxel in P-gp down-regulated group, negative control group and blank control group after48-hour0.1nM/L paclitaxel stimulation; Thirdly, the expression of P-gp protein was reduced in EphA2up-regulated NPC cells, and CCK-8assay was employed to obtain the survival rate of paclitaxel in P-gp down-regulated group, negative control group and blank control group after48-hour5nM/L paclitaxel stimulation; Fourthly, OnM/L and20nM/L PI3-K/Akt inhibitor LY294002were added to EphA2up-regulated NPC cells, and then Western Blot was employed to estimate the expression changes of Akt, p-Akt and P-gp after48-hour5nM/L paclitaxel stimulation; Additionally, the alterations of autophagy marker LC3B-Ⅱ expression in EphA2up-regulated NPC cells and parental cells after48-hour5nM/L paclitaxel stimulation were detected by Western Blot.Results:1. Separately comparing with two corresponding control groups, P-gp expression was down-regulated in EphA2down-regulated group and up-regulated in EphA2up-regulated group;2. The survical rate of paclitaxel in P-gp down-regulated group, negative control group and blank control group were52.1±3.7%v.s.72.4±6.2%,68.9±4.0%, which demonstrated that paclitaxel resistance was significantly decreased by down-regulated P-gp expression compared to two control groups (P<0.05); 3. In EphA2down-regulated NPC cells, the survical rate of paclitaxel in P-gp down-regulated group, negative control group and blank control group were36.1±5.1%v.s.58.2±5.8%,57.9±6.2%(P<0.05), which demonstrated that down-regulation of P-gp protein can reverse EphA2mediated paclitaxel resistance in NPC.4. Among EphA2over-expressed NPC cells, the expression of Akt was unchanged while p-Akt and P-gp were decreased in giving LY-294002group when compared with control group;5. The expression of LC3B-Ⅱ protein was significantly increased in EphA2over-expressed group when compared to control group.Conclusion:EphA2can regulate paclitaxel resistance in NPC cells via modulating P-gp expression, and PI3-K/Akt pathway may participate in this process. In addition, EphA2may also regulate paclitaxel resistant in NPC cells via affecting autophagy. EphA2may be a hopeful molecular target which regulating paclitaxel resistant in NPC.